FT3 to FT4 Ratio is Associated with Non-Alcoholic Steatohepatitis and Significant Fibrosis in Euthyroid Subjects with NAFLD

Background: & Aims: Studies on the relationship between thyroid function and non-alcoholic fatty liver disease (NAFLD) among euthyroid subjects had shown inconsistent results. Objective of the present study was to exploring the independent relationship between thyroid function parameters and nonalcoholic steatohepatitis (NASH), significant fibrosis (SF) respectively after adjusting other well-identified risk factors. Method: This study enrolled 307 patients with biopsy-proven NAFLD. Thyroid dysfunction defined as serum thyroid-stimulating hormone > 4.5 mIU/l or  14.41 pmol/l or < 7.86 pmol/l. Results: Stepwise regression analysis showed that the fT3/fT4 ratio, an optimal thyroid function parameter, was associated with NASH and SF in euthyroid subjects with NAFLD. After multivariable analysis, the fT3/fT4 ratio (per 0.1 change) showed significant correlation with NASH (OR 2.03(1.33, 3.11), P = 0.001) and SF (OR 2.11(1.28, 3.46), P = 0.003). When ratio was stratified by quartiles (Q1-Q4) as a categorical variable, the results still significant (Q4 versus Q1 (OR for NASH 4.29(1.68, 10.91), P = 0.002; for SF 4.63(1.49, 14.43), P = 0.008, all P for linear trend < 0.05). The prevalence of NASH and SF rose significantly with increasing in quartiles. Furthermore, ratio was positively correlated with the grade of steatosis, lobular inflammation, hepatocellular ballooning and liver fibrosis stage (all P < 0.05). Subgroup analysis showed that hypertension was a possible effect modification. Conclusion: The findings of the present study confirmed an association between fT3/fT4 ratio and NAFLD in euthyroid subjects in a dose-dependent manner, particularly in non-hypertension adults.There is no trial registration number.